Deflection system for cathode ray tubes

Abstract

The present invention relates to a display device comprising a cathode ray index tube ( 1 ) having a neck portion ( 1 ″) and a screen portion ( 1 ). The display device comprises an electron gun assembly ( 3 ) for generating a plurality of electron beams ( 3 R, 3 G, 3 B), positioned in the neck portion ( 1 ″) of the cathode ray index tube ( 1 ), a deflection unit ( 5 ), placed around the neck portion ( 1 ″) of the cathode ray index tube ( 1 ), for deflecting said plurality of electron beams ( 3 R, 3 G, 3 B), and a convergence unit ( 6 ) for converging said plurality of electron beams ( 3 R, 3 G, 3 B). The deflection unit ( 5 ) is placed at an axial distance from said electron gun assembly ( 3 ), closer to said screen portion ( 1 ′). The convergence unit ( 6 ) is placed in close proximity to the deflection unit ( 5 ).

1. A display device comprising:
 a cathode ray index tube having a neck portion and a screen portion:  
 an electron gun assembly for generating a plurality of electron beams, wherein said electron gun assembly is positioned in the neck portion of the cathode ray index tube;  
 a deflection unit, placed around the neck portion, for deflecting said plurality of electron beams; and  
 a convergence unit for converging said plurality of electron beams;  
 wherein said convergence unit is coincident with the deflection unit.  
 
     
     
       2. A display device comprising:
 a cathode ray index tube having a neck portion and a screen portion:  
 an electron gun assembly for generating a plurality of electron beams, wherein said electron gun assembly is positioned in the neck portion of the cathode ray index tube;  
 a deflection unit, placed around the neck portion, for deflecting said plurality of electron beams; and  
 a convergence unit for converging said plurality of electron beams;  
 wherein said convergence unit is in close proximity to the deflection unit, and  
 said convergence unit is placed at essentially the same axial distance from the electron gun assembly as the deflection unit.  
 
     
     
       3. A display device as claimed in  claim 2 , wherein the convergence unit comprises one or more windings wound around a yoke core in said deflection unit. 
     
     
       4. A display device as claimed in  claim 2 , wherein said convergence unit comprises two or more windings wound around separated core parts of a split yoke in said deflection unit. 
     
     
       5. A deflection system for use in a cathode ray index tube having a neck portion and a screen portion, the deflection system comprising:
 a cathode ray index tube having a neck portion and a screen portion;  
 a deflection unit, intended to be placed around the neck portion of the cathode ray index tube, for deflecting electron beams generated by an electron gun assembly placed in the neck portion; and  
 a convergence unit for converging said plurality of electron beams;  
 wherein said convergence unit and said deflection unit are formed integrally and said convergence unit is placed in close proximity to the deflection unit.  
 
     
     
       6. A deflection system as claimed in  claim 5 , wherein said convergence unit and said deflection unit are positioned in such a way that their respective centre points essentially coincide. 
     
     
       7. A deflection system as claimed in  claim 5 , wherein the convergence unit comprises one or more windings wound around a yoke core in said deflection unit. 
     
     
       8. A deflection system as claimed in  claim 5 , wherein said convergence unit comprises two or more windings wound around separated core parts of a split yoke in said deflection unit. 
     
     
       9. A display device, comprising:
 a cathode ray index tube having a neck and a screen;  
 an electron gun positioned in the neck, said electron gun for generating a plurality of electron beams;  
 a deflection unit positioned around the neck portion, said deflection unit for deflecting said plurality of electron beams vertically and horizontally; and  
 at least four convergence coils for generating a quadruple field for converging said plurality of electron beams, wherein said convergence coils are coincident with said deflection unit, and wherein said convergence coils are located at ±45° and at ±135° with respect to horizontal.  
 
     
     
       10. A display device as claimed in  claim 9 , wherein said convergence coils are wound around a deflection unit yoke core. 
     
     
       11. A display device as claimed in  claim 10 , wherein said convergence coils are wound around separated core parts of a deflection unit split yoke. 
     
     
       12. A display device as claimed in  claim 9 , wherein said deflection unit and said convergence coils are integrally formed. 
     
     
       13. A display device as claimed in  claim 12 , wherein said convergence coils and said deflection unit have coinciding center points. 
     
     
       14. A deflection system as claimed in  claim 12 , wherein said convergence coils are wound on a deflection unit yoke core. 
     
     
       15. A deflection system as claimed in  claim 14 , wherein said convergence coils are wound on separated core parts of a deflection unit split yoke. 
     
     
       16. A display device comprising:
 a cathode ray index tube having a neck and a screen;  
 an electron gun positioned in the neck, said electron gun for generating a plurality of electron beams;  
 a deflection unit positioned around the neck portion, said deflection unit for deflecting said plurality of electron beams vertically and horizontally; and  
 at least four convergence coils for generating a quadruple field for converging said plurality of electron beams, wherein said convergence coils are proximate said deflection unit, and wherein said convergence coils are located at ±45° and at ±135° with respect to horizontal,  
 wherein said convergence coils are located at substantially the same axial distance from said electron gun as is said deflection unit.